Fig 3. Caspase-11 is required to fungal clearance.
(A) WT and caspase-11-deficient mice were intravenously infected with 1x106 viable yeasts of Pb18. On the 15th and 30th day of infection, IL-1α was quantified in lungs with ELISA. (B) Lung homogenates were diluted and plated in BHI-agar medium for CFU determination according to the tissue weight. (C) Wild-type and Casp11-/- mice were challenged with 1x106 P. brasiliensis, and the survival of the Pb18-infected mice was monitored daily for 120 days. (D) P. brasiliensis was identified in the lung of respective mice after Grocott staining (magnification of 200x). Quantitative representation of the P. brasiliensis integrated density is shown. (E) Histological sections of lungs from WT and Casp11-/- mice after 30 days after infection with P. brasiliensis. The granulomatous lesion images were captured under a light microscope after H&E staining and the nuclei percentage per field was evaluated. (F) PCR analysis of mRNA expression of iNOS in the lung tissue of WT and Casp11-/- mice at 30dpi. β2m was used as a housekeeping gene. (G) Fungal growth and (H) nitrite levels quantified in WT and Casp11-/- BMDMs infected with P. brasiliensis and cultured or not with increasing concentrations of rIL-1α. (I) Casp11-/- mice infected i.v. with 1x106 P. brasiliensis cells were untreated or treated i.n. with rIL-1α (100 ng/animal) at the onset of the infection. After 30 dpi, the CFUs were measured. Error bars show the mean ± SD of 6 mice. Data are representative of three independent experiments. Statistical analysis was performed using log-rank test (Mantel–Cox) (C), non-parametric Mann-Whitney U test (A-B and F), parametric Student’s t test (D-E) or one-way ANOVA with Tukey’s multiple comparison test (G-I). (*) denotes p <0.05 compared to P. brasiliensis-infected WT mice (C57BL/6). (#) p <0.05 relative to Il1a-/- BMDMs not treated with rIL-1α. (&) indicates p <0.05 compared with non-treated Casp11-/- mice.